Science Daily December 20, 2021 Superconductivity depends on the presence of electrons bound together in a Cooper pair, but they break dissipating into two quasiparticles that hamper the performance of superconductors. It is not clear why Cooper pairs break, but the presence of quasiparticles introduces noise into technologies based on superconductors. Through an experimental set up an international team of researchers (Finland, Sweden) showed that in micron-scale aluminium superconductor separated from metallic copper by a thin insulating layer, the broken Cooper pairs the quasiparticles would tunnel through the insulation to the copper. The Cooper pairs break in bursts, with seconds […]
New materials for quantum technologies
Phys.org December 22, 2021 To advance spintronics devices and quantum information technology using materials with non-trivial topological properties, three key challenges are still unresolved – the identification of topological band degeneracies located at the Fermi level, the ability to easily control such topological degeneracies., and the identification of generic topological degeneracies in large, multisheeted Fermi surfaces. Researchers in Germany have shown that the non-symmorphic symmetries in chiral, ferromagnetic manganese silicide (MnSi) generate nodal planes (NPs) which enforce topological protectorates (TPs) with substantial Berry curvatures at the intersection of the NPs with the Fermi surface (FS) regardless of the complexity of […]
Novel biosensors set to revolutionize brain-controlled robotics
Science Daily December 22, 2021 Researchers in Australia have detected the EEG signals with high sensitivity using epitaxial graphene (EG) grown on silicon carbide on silicon. The dry and non-invasive approach exhibited a markedly improved skin contact impedance when benchmarked to commercial dry electrodes, as well as superior robustness, allowing prolonged and repeated use also in a highly saline environment. They observed a new phenomenon of surface conditioning of the EG electrodes. The prolonged contact of the EG with the skin electrolytes functionalize the grain boundaries of the graphene, leading to the formation of a thin surface film of water […]
An Omicron investigator, a Mars explorer and an AI ethics pioneer are some of the people behind the year’s big research stories. (video)
Nature December 15, 2021 The Nature’s 10 list explores key developments in science this year and some of the people who played important parts in these milestones. Along with their colleagues, these individuals helped to make amazing discoveries and brought attention to crucial issues. Nature’s 10 is not an award or a ranking. The selection is compiled by Nature’s editors to highlight key events in science through the compelling stories of those involved…. read more.
Quantum marbles in a bowl of light
Science Daily December 22, 2021 Quantum mechanics sets fundamental limits on how fast quantum states can be transformed in time. Two well-known quantum speed limits are the Mandelstam-Tamm and the Margolus-Levitin bounds, which relate the maximum speed of evolution to the system’s energy uncertainty and mean energy, respectively. An international team of researchers (Israel, Germany) tested concurrently both limits in a multilevel system by following the motion of a single atom in an optical trap using fast matter wave interferometry. They found two different regimes: one where the Mandelstam-Tamm limit constrains the evolution at all times. But there was also […]
Redrawing the lines: Growing inexpensive, high-quality iron-based superconductors
Phys.org December 17, 2021 The technique of ion irradiation to enhance the dissipation-free supercurrent in the presence of a magnetic field for type II superconductors is complicated and expensive. An international team of researchers (Japan, USA – Florida State University) has developed an inexpensive, scalable way to produce high-temperature superconductors using grain boundary engineering techniques. They grew iron-based superconductors (FBS) called “potassium-doped BaFe2As2 (Ba122) using molecular beam epitaxy, in which the superconductor is grown on a substrate. It had high pinning efficiency without artificial pinning centers (APCs). Measurements of the thin film’s electrical resistivity and magnetic properties showed that the […]
Researchers develop new measurements for designing cooler electronics
Science Daily December 21, 2021 Often the thermal energy generated in the device during operation must cross several dissimilar materials during the process and the interface between these materials can impede heat flow. An international team of researchers (Georgia Institute of Technology, University of Notre Dame, UC Irvine, US.S. Naval Research Laboratory, UCLA, Oak Ridge National Laboratory, South Korea) observed the interfacial phonon modes experimentally at a high-quality Si-Ge epitaxial interface by using Raman Spectroscopy and high-energy resolution electron energy-loss spectroscopy (EELS). To figure out the role of interfacial phonon modes in heat transfer at interfaces, they used time-domain thermoreflectance […]
Scientists successfully manipulate a single skyrmion at room temperature
Nanowerk December 17, 2021 The key to creating spintronics devices is the ability to effectively manipulate, and measure, a single skyrmion. Researchers in Japan used a thin magnetic plate made up of a compound of cobalt, zinc, and manganese, Co9Zn9Mn2 to observe the dynamics of a single skyrmion at room temperature. They were able to track the motions of the skyrmion and control its Hall motion directions by flipping the magnetic field when they subjected it to ultrafast pulses of electric current—on the scale of nanoseconds. They found that the skyrmion’s motion demonstrated a dynamic transition from a pinned static […]
Soft semiconductors that stretch like human skin can detect ultra-low light levels
Science Daily December 15, 2021 An international team of researchers (USA – Georgia Institute of Technology, Chile) has demonstrated a new level of stretchability for a photodetector made from a synthetic polymer and an elastomer that absorbs light to produce an electrical current. It is up to 200% more stretchable than its original dimension without significantly losing its electric current. They found the right combination of chemical compounds to produce a super-soft material with the ability to generate and conduct electricity when exposed to light and the right ratio for all parts of the semiconductor layer to maintain high performance […]
Study shows that zwitterions can raise the dielectric constant of soft materials
Phys.org December 17, 2021 To create efficient energy storage solutions and actuators, engineers need materials with high dielectric constant. The current method of incorporating polar additives with a high dielectric constant has not yielded high enough dielectric constant for many applications. Researchers at Penn State University have demonstrated a new method for raising the dielectric constant by adding zwitterions, small molecules with one positive electrical charge and one negative electrical charge separated by covalent bonds. Zwitterions are non-volatile molecules that are highly polar. In their recent experiments, the team added the zwitterions to polymeric single-ion conductors. Zwitterions raised dielectric constant […]